Metal-cutting chain saw



United States Patent Inventor Russell F. Rogers Youngstown, Ohio (589 Allegheny Trail, Negley, Ohio 44441) Appl. No. 725,253

Filed Apr. 16, 1968 Continuation-impart of Ser. No. 534,892, Mar. 16, 1966, abandoned. Patented Nov. 3, 1970 METAL-CUTTING CHAIN SAW 32-4, 32-10, 135; l44/72, 73; 83(lnquired),20l

j [56] References Cited UNITED STATES PATENTS 951,5l0 3/1910 Muir.... l43/32 1,016,664 2/1912 Bailey 143/32 Primary ExaminerDonald R. Schran Attorney-Peter L. Klempay ABSTRACT: A chain saw of the milling cutter type adapted to the cutting of ferrous and nonferrous metals, and having special provisions to prevent chattering or jerking of the cutter chain. The cutter chain is entrained over a backup bar and a pair of sprockets. The peripheral edges of the backup bar are provided with a dovetail slot and the links are provided with a dovetail projection which is received in this slot. The drive sprocket is fixed relative to the backup bar while the takeup sprocket is spring-biased to maintain tension of the cutting chain. A pair of arms are arranged to contact the opposed faces of the backup bar on its vertical centerline adjacent the point of entry of the bar into the metal being cut to guide the bar and to prevent any wobbling.

Patented 3, 1970 I 3,537,347

Shoot 1 of 3 F ll INVENTOR.

3 RUSSELL a ROGERS I KTTQRNEY v I PatentdiNOv. 3,1970 I I I 3,537,347

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INVENTOR.

RUSSELL F] ROGERS v AGENT METAL-CUTTING CHAIN SAW This application is a continuation-in-part of (as to all common subject matters) of my copending U.S. Pat. application, Ser. No. 534,892, filed March 16, 1966, now abandoned for improvements in Metal-Cutting Chain Saw", which application will now be permitted to lapse without prejudice, in view of its being superceded by this present application.

This invention relates to a chain saw of the milling cutter type especially adaptable to the cutting of ferrous and nonferrous metals. As such, the apparatus of the invention relates to a chain type of milling cutter or broach in which a cutting bit, preferably of a carbide type, is detachably carried by each of the links of the chain. In order for such a device to operate satisfactorily when cutting the tougher steels, particularly, it is absolutely essential that the cutting bits be accurately guided and restrained against chattering and be capable of having applied thereto substantial motive power to effect a continuous and uninterrupted cutting action through or across the work. It is well recognized in the machining art-that cutting speed and penetration, control of penetration and the continuous application of motive power are important factors in the proper operation of toothed cutting devices.

The primary object of the invention is the provision of an improved chain assembly for carrying the cutting hits as well as an improved guiding assembly for channeling the path of movement of the individual chain links and bits along the predetermined cutting path. This general object is achieved, in accordance with the invention, by providing a novel and improved sliding interconnection between the cutter links and a backing bar which predetermines the path of chain travel, by so constructing the chain itselfthat the individual links thereof are inherently restrained against any unwanted movement, and by providing an improved-means for keeping the chain taut to thereby assist its guiding while reducing its wear. Further, the construction of the apparatus is such that very substantial motive power may be applied to the chain to take full advantage of the efficiency of carbide cutting bits without inducing excessive vibration or chattering to the chain and thus provide a cutting device which is rapid and highly efficient in operation and capable of heavy service over substantial periods of time.

The above and other objects and advantages of the invention will become apparent upon consideration of the following specification and the accompanying drawing wherein there is disclosed a preferred embodiment of the invention.

In the Drawings:

FIG. 1 is a schematic showing of a chain-type of cutting assembly constructed in accordance with the principles of the invention;

FIG. 2 is a transverse sectional view of the apparatus of FIG. 1, the view being taken along the line II-II of FIG. 1;

FIGS. 3 and 4 are plan and side elevational views, respectively, of one of the chain links used in the assembly of FIGS. I and 2;

FIG. 5 is a fragmentary sectional view of the sliding interconnection between one of the chain links and the mounting bar of the cutter assembly;

FIGS. 6 and 7 are plan and side elevational views, respectively, of one of the chain links used in a modified form of my invention; and

FIGS. 8 and 9 are side elevational views of the components ofthe link shown in FIGS. 6 and 7.

The essential elements of the saw of this invention are mounted on a slablike backing bar 10 which is elliptical in shape, as shown in FIG. I. This bar 10 has rigidly attached to it at its ends and on either face thereof brackets 11 and 12, the latter of which rotatably support a transverse shaft 13 which is arranged to be power driven by suitable means, not shown, and to which is keyed a sprocket l4 lying between the two brackets 12 and in planar alignment with the bar 10. The brackets 11 each has a horizontally elongated window 15 therein in which is slideable a bearing block 16 for journaling a transverse shaft 17. Shaft 17 carries an idler sprocket 18 which lies between the two brackets 11 and again is in planar alignment with the bar 10. Shaft 17 and the sprocket 18 carried thereby are made movable to apply proper tension to the cutter chain which is entrained over the sprocket. For this purpose I provide bolts 20' the heads of which are received behind flanges 20 formed on the block 16 and which are slideable in apertures formed in flanges II' formed integrally on the brackets 11., Stiff compression springs 19' are interposed between the nuts 19 and the flanges 11' the nuts 19 being, of course, screw-threaded on the outer end portions of the bolts 20'.

The upper and lower edges of the bar 10 have dovetailed slots 21 machined in them to slideably receive the dovetailed ribs 22 formed integrally on the cutter links which are designated generally by the reference numeral 23 and which will now be described in detail. Each of the links 23 is formed of an elongated piece of flat stock and is forked or bifurcated at 24 on one end and tongued at 25 at the other end whereby the links may be suitably joined together by hinge pins in the normal manner. One major edge of each link (and the rib 22 carried thereby) is curved slightly to complement exactly the curvature of the upper and lower edges of the bar 10 on which the chain rides. The opposite major edge of each link is recessed, as shown at 26 in FIG. 4, to receive a cutter bit 27 and a keeper 28. In accordance with known tooling practice the bit 27 is preferably a hard metallic carbide and is mounted on a stud driven into the body of the link, as shown, while the keeper 28 is detachably secured to the body of the link by a recessed head screw, the general arrangement being such that the individual cutting bits may be readily replaced from time to time as breakage or excessive wear occurs.

An alternative construction of the links is shown in FIGS. 6-9. Each of the links 23' is formed ofa pair of outer plates 48 and an inner plate 49, the configuration of these plates being illustrated clearly in FIGS. 8 and 9, respectively. The end 50 of the inner plate 49 which provides the tongue of the assembled link has a step 51 at the horizontal center line of the end of the link. The opposite end 52 of the plate 49 has a corresponding step 53. When the links 23 are assembled into a continuous chain, the steps 51 and 53 of the inner plates of the links prevent the chain from moving beyond a straight to a concave position and thus prevent chattering of the individual links of the chain. The close-mating of the complimentary surfaces 54 and 55 of adjacent links provide a seal in the region of the steps 51 and 53 and thus prevent any chips or fragments of metal from entering this region preventing the chain from being drawn straight when in the cutting region. The metallic carbide bit 27 is grooved along its bottom and one side edge, and these grooves mate with a projecting portion 56 of the inner piece of the link 23 A bolt 57 secures the bit 27 to the link and the projection 56 prevents movement of the bit 27' relative to the link. 1

As stated initially in this specification, it is essential that th cutting bits be accurately guided and restrained against chat tering if metallic objects are to be cleanly cut at a rapid rate utilizing the very substantial rapid cutting potential of carbide tools and properly channeling the very substantial motive power, which such tools require. Contributing significantly to the solution of this problem is the sliding dovetailed interconnection between the cutter chain links and the backup bar 10 but I have found that it is desirable to reinforce this characteristic since in actual practice the transverse dimensions of the ribs 22 in relation to the slots 21 must be made fairly free to reduce friction and heating and since normal wear between the sliding parts does tend to loosen up the guiding of the chain. One difficulty which has theretofore been experienced is the tendency of the individual chain links to rock very slightly about transverse axes as the links are successively brought into contact or pressure engagement with the work. This makes for chattering and the resultant increase of wear on the links and cutting bits and sometimes in the fracture of the cutting edges of the bits. To absolutely restrain suchrocking action, I provide a flat surface 29 at the bottom of the bifurcation 24 of each link and another flat surface 30 on the outer end of the tongue 25 of each link. The relative angularity of the flat surfaces 29 and 30 is such that as the links traverse the curvature of the bar the end surfaces 30 lie in tight overlying relation to the flat surfaces 29 of adjacent links. This enables the chain to entrain about the smaller radius of the sprockets l1 and 14, but as the links traverse the larger radii of the bar 10 no part of any link can rock inward with respect any parts of adjacent links. This positively avoids chattering.

Rigidly connected to and carrying the two brackets 11 is a pair of transversely space depending supports 30, and a similar pair of supports 31 carry the brackets 12. Rigidly carrying the upper ends of the supports 30 and 31 is a horizontally disposed frame 32 which is suitably guided for vertical up and down movement in a machine structure and by hydraulic or other moving mechanism not particularly shown herein except that the vertical guiding surfaces of the frame 32 are shown schematically at 33 in FIG. 2. It will be apparent that by raising and lowering the frame 32 the bar 10 and the cutter chain carried thereby is likewise raised and lowered and it is also possible to apply a substantial downward force to the bar 10 and cutter chain to cause the latter to bite into and through the work. A workpiece is shown schematically at 34, being held by a suitable clamp or vise 35 which,'in accord with common practice, is also carried by the main structure by the cutting machine.

In the actual practice of this invention the bar 10 as well as the cutter chain carried thereby may be made quite long 60 inches for example, and in order to laterally stabilize the center portion of such a long blade I provide a pair of depending bars 36 which are rigidly connected at their upper ends to the frame 32 and which have applied to the inner faces of their bottom ends wear blades 37 which slide against the opposite faces of the bar 10. To lend further lateral stability to the whole assembly and particularly to prevent the individual cutter links of the chain from vibrating or chattering laterally at the start of a cut, I provide additional depending bars 38 which are hinged at their upper ends to a carrier 39 which is arranged to float up and down with respect to the frame 32, suitable guiding rollers 40 being provided to effect the guiding of the carrier 39 with respect to the frame 32.

Suitable means, such as the fluid pressure cylinders 41, is provided to keep the lower ends of the bars 38 in pressure contact with the side edges of the chain links 23. Suitable hardened inserts 44, preferably of a metal carbide or of Stel lite", may be provided to resist wear on the inner lower ends of the arms 38 by the rapidly moving chain. It will be obvious to those skilled in the art that the cylinders 41 are preferably of the double-acting kind and supplied with hydraulic fluid pressure so that by means of known control valves the piston rods ofthese cylinders may be locked in adjusted position with a controlled degree of pressure exerted through the wear blocks 44. With this arrangement it is obvious that the center portion of the bottom reach of the cutter chain will be effectivcly restrained against any tendency to overturn at the start of a cut. This restraint is in addition to that provided by the dovetail interconnection 21, 22.

The thickness of the links 23 of the cutter chain is exactly equal to the thickness of the bar 10 so that as the cutter chain bites into and become embedded in the work, the wear blocks 44 can simply ride up the outer faces of the bar 10, the floating nature of the carrier 39 permitting this as will be understood. In actual practice the cutting bits 27 are preferably made slightly wider than the thickness of the links 23 and of the bar 10 to eliminate binding of the bar in the groove cut in the work but the bar 10 is yet held against side-to-side flexing by the wear blocks 44. However, if the depth of cut is to exceed a predetermined dimension it may be necessary to withdraw the arms 38, which can be readily accomplished by reversing the flow and pressure of hydraulic fluid to the cylinders 41. Also, it may be necessary, if extreme or through penetration is to be of the arms 36 to the frame 32. Obviously, wing nuts or other suitable expedients may be used to facilitate the removal of the arms 36.

To further stabilize the lower reach of the cutter chain laterally with respect to the bar 10, l'additionally provide heavy clips 46 on either face of the bar 10 and outwardly of the longest workpiece which can be accommodated between the clamps 35. As shown, these clips project downwardly below the edge of the bar 10 to ride against the side faces of the links 23.

As shown in FIGS. 3 and 4, a driving slot 47 is cut into the inner edge of each of the links 23 of the chain, and it will be obvious that the sprockets 11 and 14 will be constructed with narrow driving teeth which fit into these slots 47. Such teeth may be cut integrally with the body portions of the sprockets although it is contemplated that the same may be provided by embedding or attaching narrow disks to the peripheries of the wheels 11 and 14 at points properly spaced circumferentially. The driving arrangement of the slots 47 is highly advantageous because the same does not interfere with the action of the dovetail interconnection 21, 22 or with the production machining of either the dovetail slot 21 or the complementary dovetailrib 22. Since the upper and lower edges of the bar 10 have fixed radii, these edges, including the slots 21, may be machined on a lathe and, likewise, with suitable fixturing, the curved inner edges of the links 23, including the ribs 22, may be readily machined on a lathe with great precision.

Having thus described my invention what I claim is:

I claim:

1. A metal-cutting chain saw, comprising: an elongated slablike backing bar having principal opposed edges uniformly curved about axes normal to the plane of said bar and space substantially outward of the longitudinal axis of said bar; a driven sprocket at one end of said bar, lying in the plane thereof; a takeup sprocket at the other end of the said bar, also lying in the plane thereof; one of said sprockets being biased for movement away from said bar along the longitudinal axis thereof; an endless chain entrained over said sprockets and said opposed edges of said bar; and means providing guiding surfaces which partially overlie the opposite side edges of said bar and the opposite side edges of said links.

2. Apparatus according to claim 1 further including additional means to apply inward pressure to said means providing said guiding surfaces and to thereafter lock said last mentioned means in adjusted position, and said additional means being retractable when desired to allow the entire vertical extent of the assembled backing bar and cutter chain to pass entirely through the workpiece' 3. Apparatus according to claim 2 further including means for mounting said guiding surface providing means and said additional means in floating relation with respect to said backing bar and chain to permit the latter to move into the workpiece while the guiding means yet remains operative to restrain lateral movement of said backing bar.

4. Apparatus according to claim 3 further including a guided movable frame for supporting said backing bar and sprockets as well as the chain whereby the latter can be forced into and retracted from the workpiece, and said additional means being floatingly mounted on said frame.

5. A metal-cutting chain saw, comprising: an elongated slablike backing bar having principal opposed edges uniformly curved about axes normal to the plane of the bar and spaced substantially outward of the longitudinal axis of said bar; a driven sprocket at one end of said bar, lying in the plane thereof; a takeup sprocket at the other end of said bar, also lying in the plane thereof; one of said sprockets being biased for movement away from said bar along the longitudinal axis thereof; an endless chain entrained over said sprockets and said opposed edges of said bar, each of the links of said chain terline being of a second, larger radius, and the recessed portion of said bifurcated end being of a complementary configuration. 

